Angiotensin converting enzyme (ACE) inhibitors are widely used in the treatment of hypertension, congestive heart failure, acute myocardial infarction and diabetic nephropathy. One of the side effects that is often observed in patients who are taking ACE inhibitors is a persistent, dry cough that is refractory to most commonly prescribed cough suppressants. The cough is sometimes so severe that therapy with the ACE inhibitor must be discontinued.
Even those patients who respond to conventional cough suppressants are subject to the disadvantages associated with long term use of opiates and other non-opiate cough suppressants.
In the prior art, baclofen has been described as a GABA.sub..beta. agonist which has antitussive effects. Br. J. Pharmacol.(1993)110, 491-495) These effects have been demonstrated by counting the number of coughs elicited during a 4 minute or 30 minute period against capsaicin challenge by subcutaneous administration or by inhalation when baclofen and other antitussives were administered.
The present invention provides a method of suppressing the cough that is observed in patients, who are being maintained on an ACE inhibitor, which comprises the coadministration of baclofen with the ACE inhibitor. Based on the published literature, it was surprising and unexpected that no substantial antitussive effect, which could be attributed to the coadministration of baclofen with the ACE inhibitor, is observed until about three days after the initiation of baclofen therapy.